Emission material won't work while another emission in my scene is on
It's an issue with object size, basically it seems like Blender can't find your lamp filament.

Actually the emission is still working, only it's influence is being disregarded because it can't be found easily. In theory with an unpractical amount of samples it would eventually become visible. If you increase the number of preview samples to an insane amount the light will actually start to become visible in the form of very spaced fireflies.

The Cycles rendering algorithm is having trouble finding your very tiny light source (lamp filament) when there is a comparatively very big and bright light source around (neon sign).

My advice to you is that it's not recommended to use such small light sources, hidden away behind so many layers of glass, as actual means of lighting up your scene.

Fake the light coming from the filament, and add an actual lamp object in its place instead to actually light up your scene.

Also see https://blender.stackexchange.com/a/65171/19307